How do you add a rusted finish look on SS knife?

S

St33L

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Dec 18, 2013
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I'm wondering if it's possible to add a slightly "rusted-over" finish appearance on, say, a stainless super steel like M390.

The rusted look would be like what you'd see on an old carbon knife left in the garage for some years, but which isn't terribly rusted over and fubar.

It would have a dark grayish-slightly reddish brown tone to it, as if it's some sort of matte coating (similar in finish to the rusted image below, a bit darker though with less of a reddish tone).

So, it won't actually be rusted, per se, but it will have the appearance.

I'm interested in this sort of look for areas where you'd typically see brute de forge or hammered finishes applied (e.g. on the blade flat or fuller area).

Would it actually be rusting of the stainless steel to achieve that look? If so, would such a finish be ok to leave that area alone without maintenance because it's an SS blade (e.g. the light rust acts as a protective layer)?

Thanks in advance.


FGKEB2CFWYHRWEE.LARGE.jpg
 
So you're asking how to patina a stainless steel?

I've got no idea, but I'll be interested to see if anyone knows of a way.
 
ocnLogan said:
So you're asking how to patina a stainless steel?

I've got no idea, but I'll be interested to see if anyone knows of a way.
Click to expand...

Yes, that's exactly what I mean. For some odd reason, that word escaped me!

Natural patina that almost looks as if it has rust, but the stainless steel is protected by that patina from rust.
 
Ferric chloride is probably your best best; copper plating achieves a neat effect as well; pic below (not mine):

i016113g-z.jpg


Or, possibly a combo of the two, FC etch followed by the copper plate bath - I believe I've seen something to that effect done before. :thumbup:
 
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Forced patinas usually (in my pretty limited experience) do not look red or brown like rust. They are more grey.

If you want the stainless blade to rust evenly, applying coats of salt water would probably do the trick. If not, You could try to rig up asaltwater mister, or even just dunk it. You might have to mess around with the pre-rusting finish on the blade. Maybe patina first with ferric for the matte look, then saltwater after to spot with rust, or vise versa. It would be an interesting experiment with some scrap steel. How dangerous any of this is in terms of causing deeper pitting etc I do not know, but I'd definitely try to keep the rust off the edge bevel area (fingernail polish?).
 
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You are wanting to have a material specifically designed NOT to do something do it.

The short answer is NO.

The long answer is possibly, but it is unlikely that the results would be satisfactory and would take a lot of work to achieve something "similar" to what you are looking for.

I'm afraid to know the answer, but why don't you just use carbon steel instead for your project, instead of messing up a good piece of stainless?

Best Regards,

STeven Garsson
 
I use muratic acid to coat the blade, then immediately coat with super blue cold blue. You get immediate reaction and it Will patina SS. Be extremely careful using this as the fumes could be very harmful.
 
According to the product in the link below, it's possible via ferric nitrate. Not sure what color will result though. But the video below shows a brown patina on steel, not sure what would happen on stainless.

http://www.sculptnouveau.com/Details.cfm?ProdID=34

[video=youtube;iTgjAVuY-cg]https://www.youtube.com/watch?v=iTgjAVuY-cg&list=PLAFF2359421782D8B&index=2[/video]
 
I did the acid wash on this Larry Page hunter of mine. It is CPM154 and was a mirror finish when I got it. I just used the good old ferric chloride PCB etch solution from Radio Shack. I've done this to a number of non stainless blades as well (1095 and 3V). This is the only stainless I've tried but it turned out well.

 
If you decide to copper plate, here is a little trick:
Take it to a radiator shop, dip the blade in the hot tank. The mercuric acid is loaded with copper, after 3 or 4 radiators are soaked.
The radiator shop might not even charge you. :)

I inadvertently copper plated a LLama .45 frame and slide once, when I used the hot tank at the shop I worked at to de-blue it.
 
hori-garden-knife-before-large.jpg


Here's a stainless steel that is given an oxide layer to the Hori Garden Knife blade, which "has a fairly heavy gray-purple oxide layer from the 3-stage heat-treat process: 7 hours at temperatures from 925 – 2100ºF".

Will this work on M390? The oxide layer above on stainless steel is exactly what I want it to look like on stainless steel - but I'm sure that not all stainless steels are created equally with respect to oxidizing... but maybe all stainless steels will take effect similarly?

Here's the source link:

http://diggitinc.com/diggit-hori-garden-knife.html
 
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That means basically that the gunk from heat treatment was left on without cleaning.

You could pre-polish, then heat treat and then not clean the blade. That would give a similar result to the above example.

However it could also result into funky colours. I recently got an M390 blade back from heat treat and it was a golden colour all over.

So your results WILL vary...especially with something like M390 which is notoriously difficult to heat treat.
 
LX_Emergency said:
That means basically that the gunk from heat treatment was left on without cleaning.

You could pre-polish, then heat treat and then not clean the blade. That would give a similar result to the above example.

However it could also result into funky colours. I recently got an M390 blade back from heat treat and it was a golden colour all over.

So your results WILL vary...especially with something like M390 which is notoriously difficult to heat treat.
Click to expand...

Ahh I see - as long as it's possible to get that rusted patina look on stainless steel, I've learned something simple yet amazing looking can happen.
 
Once I get home I'll show you what M390 can look like post heat treat. I still have a few unfinished blades lying around.
 
Zuchus said:
I did the acid wash on this Larry Page hunter of mine. It is CPM154 and was a mirror finish when I got it. I just used the good old ferric chloride PCB etch solution from Radio Shack. I've done this to a number of non stainless blades as well (1095 and 3V). This is the only stainless I've tried but it turned out well.

Click to expand...
Very nice. How did you make it that even? A soak? Sometimes I think I get a greenish tinge from PCB etch.

When I engraved this thing with the Elvish script it ended up pretty rough in the bottom of the engraving. I filled the characters with PCB etchant and let it sit for a long while to camouflage that.


I wish I knew what acid they used in metal etching pens. That gives a nice black color. The best you can get from Ferric Chloride is a light grey.
 
Well... There are a lot of recipes out there. As someone already mentioned the infamous ferric acid thingy, I suppose you people do have access to chemicals.

Look up (mostly metalography sites like struers, buehler, atm and the likes):
-V2A etchant
-Etchant according to Adler

However: be advised that this stuff is meant to be used by professionals with proper personal safety wear/kits and a certified hood! Some recipes are rightout nasty, produce highly toxic fumes and splashes on the skin will get you hospitalized.
Also if you're working somewhere in a quality department you could try to access ASTM E407. Tons of information on etchants for all kinds of metals and alloys. Be sure you know how to mix an acid though, the order is acid into water/alcohol NOT THE OTHER WAY AROUND. Never pour liquid into a concentrated or diluted acid. Basic chemistry applies here. The ASTM makes the impression you get acid mixed first and pour water or whatever into it. This will produce NASTY results like spontaneously heating up, starting to boil in splitseconds or rightout explode into your face. Or you can get a copy of "G. Petzow - Metallographisches, keramographisches und plastographisches Ätzen" not sure whether it's been translated into English yet. Also very good advice on how to grind and polish things in there.

Most of the time you want macro etching for a rustic look. Be sure to understand what the etchant does, generally you don't want to reveal segregation zones, delta phases or rolling/fiber orientation.
Also you could look into color etchants if you're not using the knife for food preparation. Greenish or reddish tints are possible with that, too. If in doubt ask someone with a chemistry background.
 
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